[automerger skipped] Check for system_other existence in recovery mode as well. am: ddf27738af -s ours

am skip reason: Change-Id I1884755aad2a8d37f540dbee73c7c7baab2759e7 with SHA-1 13e4195d65 is in history

Original change: https://googleplex-android-review.googlesource.com/c/platform/system/update_engine/+/11796618

Change-Id: Ie5831db87df958c5444ce3ae07829d62451a7c34